Filling material, especially for pillows, should be lightweight, resilient and flexible, so that it retains its shape and does not become flattened or crushed permanently. It should be soft to provide comfort when used as a head rest, but it should retain its shape so that the filling does not move to one end or the other. It is also desirable that it should be easily cleaned and that it should not deteriorate rapidly with age.
Natural materials such as down, cotton wadding or batting, kapok, horsehair, tow batting and the like have been used in the past for such filling materials, but are now being replaced by latex and synthetics. Flexible foam materials such as foam latex and foam polyurethane have many advantages. However, they do not have the comfort or luxury of down and are unsuitable for thermal insulation. They are also expensive since the material required to fill a given volume is relatively great.
Another much-used filling material, particularly for the cores of pillows, is composed of fibers. Polyester fibers are especially popular, even though they tend to bunch up and create pockets which permit the pillow to "bottom out".
Some efforts have been made to combine foam pieces with fibers, but these tend to "clump" together as the foam pieces become entangled with the fibers. These efforts culminated in the filling material of the cited application which is created by shredding polyethylene foam of a predetermined density and indent load deflection into chips or roughly square blocks of about average of one-quarter (1/4) inch square. The foam chips may be collected in a bag after shredding and fed into a hopper.
At the same time, polyester fiber composed of any fiber-forming substance which is a long-chain synthetic polymer is prepared. Fibers coated or slickened with a finish such as silicone and of average length of about 2 inches are prepared and then mixed in a tumbler with the foam in an average ratio of 60% foam to 40% fiber. The resultant product is a homogeneous fiber-foam filling material which performs well as a pillow core, or as a filler for comforters, cushions and upholstered items result.
The density of the starting foam material is not critical, but foam of a density of 0.8 to 1.3 lbs. per square foot and an indent load deflection (ILD) of 8 to 20 lbs. has proven satisfactory. The ILD of such polyurethane foam is defined as the amount of weight required to reduce a square block of foam of 16".times.16".times.4" thickness down to a thickness of 3". Such foam has been commonly used alone with no other materials as filler for pillows in ranges of 0.8 to 1.2 lbs. density and an ILD of about 10 lbs.
The foam is then shredded into chips or roughly square blocks of about one-eighth to one-half inch per side. Desirably, the average chip or block is about one-quarter inch square. The shredding is accomplished in a conventional foam shredding machine, the foam chips are collected in a bag and placed in a hopper.
Polyester fiber is prepared at the same time. The fiber-forming material may be any long-chain, non-cellulosic synthetic polymer. The fibers should have certain qualities, including crease resistance, quick-drying capabilities, shape retention, high strength and abrasion resistance.
As to size of the fiber, that is not critical, but 5 to 15 denier, averaging about 6 denier for use with the average quarter-inch foam chips, has performed well. Finally, the fiber should be coated or slickened with a finish such as silicone. In addition to enhancing washability, resilience, and durability, the slickened fibers are capable of limited movement relative to themselves and to the foam chips.
For use with the average quarter-inch foam chips, fiber of 1.25 to 3 inches in length, averaging about 2 inches, has proven superior. The fibers are mixed with the foam chips in a ratio of 30% to 50% fiber to 70% to 50% foam (averaging 60% foam to 40% fiber) in a tumbler to produce a homogenous fiber-foam material for filling pillow cores, comforters, upholstered items and the like. The length and denier of the fibers relative to the size of the chips plus the limited movement facilitated by the slickened surface of the fiber affords the user a feeling of comfort while maintaining shape and providing adequate support.
Fiber suitable to be prepared for use in the invention is available commercially under various trade names, such as FILWELL II, which is a solid polyester fiber of 6 and 15 denier slickened with silicone, or FILWELL III, which is a hollow polyester fiber of 6, 8, 12 and 15 denier slickened with a silicone coating. The manufacturer of these fibers is Wellman, Inc. of Johnsonville, S.C. Similar fibers are available from several manufacturers, including E.I. duPont de Nemours & Co. of Wilmington, Del.
Although the filling material of the invention permits the making of superior pillows and other cushioning articles, there has not been available a casing of sufficient quality to bring out to the fullest the inherent advantages of the new filling material. In fact, the commonly used casing is made of ticking which may be made of linen, canvas, or other rugged but relatively thin fabric.
It is therefore a primary object of the present invention to provide a pillow having a casing which includes a pouch of relatively soft material having a predetermined surface texture.
It is a further object of the present invention to produce a pillow which includes a resilient casing and a fiber/foam filling material which does not "bottom out".
Another object is to provide a casing or pouch made of foam which can be economically and easily made to form pillows of various sizes.
Still another object is to provide a foam pouch for a pillow which can be made by stitching, heat-sealing, or cementing.
Yet another object is to provide a pillow having a casing which may be formed using convoluted layers of foam compressed and severed in predetermined patterns.